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Publications


Submitted

2012

N., MM.  2012.  Antiplasmodial Quinones from Pentas longiflora and Pentas lanceolata. Planta medica. 78 :31–35. Abstract

The dichloromethane/methanol (1:1) extracts of the roots of Pentas longiflora and Pentas lanceolata showed low micromolar (IC(50) = 0.9-3 µg/mL) IN VITRO antiplasmodial activity against chloroquine-resistant (W2) and chloroquine-sensitive (D6) strains of PLASMODIUM FALCIPARUM. Chromatographic separation of the extract of PENTAS LONGIFLORA led to the isolation of the pyranonaphthoquinones pentalongin (1) and psychorubrin (2) with IC(50) values below 1 µg/mL and the naphthalene derivative mollugin (3), which showed marginal activity. Similar treatment of Pentas lanceolata led to the isolation of eight anthraquinones ( 4-11, IC(50) = 5-31 µg/mL) of which one is new (5,6-dihydroxydamnacanthol, 11), while three--nordamnacanthal (7), lucidin-ω-methyl ether (9), and damnacanthol (10)--are reported here for the first time from the genus Pentas. The compounds were identified by NMR and mass spectroscopic techniques.

2009

M.N., M.  2009.  8-METHOXYNEORAUTENOL AND RADICAL SCAVENGING FLAVONOIDS FROM ERYTHRINA ABYSSINICA. Bulletin of the Chemical Society of Ethiopia. 23(2):205-210. Abstract

A new pterocarpan (named 8-methoxyneorautenol) was isolated from the acetone extract of the
root bark of Erythrina abyssinica. In addition, the known isoflavonoid derivatives eryvarin L, erycristagallin and
shinpterocarpin were identified for the first time from the roots of this plant. The structures were determined on
the basis of spectroscopic evidence. The new compound showed selective antimicrobial activity against
Trichophyton mentagrophytes. The acetone extract of the root bark of E. abyssinica showed radical scavenging
activity towards 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The pterocarpenes, 3-hydroxy-9-methoxy-10-(3,3-
dimethylallyl)pterocarpene and erycristagallin, were the most active constituents of the roots of this plant and showing dose-dependent activities similar to that of the standard quercetin.

2007

  2007.  CONVERSION OF VERNONIA GALAMENSIS OIL TO PYRIDINO-VERNOLAMIDES AND THEIR ANTIMICROBIAL ACTIVITIES. Bull. Chem. Soc. Ethiop. . 21(1):1-8. Abstract

Vernonia oil extracted by Soxhlet extraction from the seeds of Vernonia galamensis
ssp. nairobensis was reacted with 2-aminopyridine, 2-(aminomethyl)pyridine and 2-
(aminoethyl)pyridine using a 1:3 mole ratio of vernonia oil to amine at varied temperatures to give
the corresponding vernolamides. The expected vernolamide from the reaction of 2-aminopyridine
and the oil was not formed. N-(2-pyridinylmethyl)vernolamide and N-(2-
pyridinylethyl)vernolamide exhibited antibacterial activity that was shown to be higher against
gram-positive (Bacillus subtilis) than gram-negative (Escherichia coli) bacteria. The vernolamides
did not show any antifungal activity.

2006

Mbugua, MN.  2006.  Synthesis of aminoalkyl vernolamides from vernonia oil at varied conditions. Journal of Kenya Chemical Society. 3(1):1-8. Abstract

The oil extracted from the seeds of Vernonia galamensis ssp. nairobensis was reacted with 1,6-diaminohexane and 1,8-diaminooctane using a 1:3 molar ratio of vernonia oil to amine to give the corresponding vernolamides. Varied temperatures and solvents were applied. The vernolamides exhibited antibacterial activity against gram-positive (Bacillus subtilis) and on gram-negative (Escherichia coli) bacteria. The vernolamides did not show any antifungal activity.

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